The US has pulled out its ambassador to Syria, Robert Ford, because of concerns for his safety, officials say.
Mr Ford angered Syrian authorities by showing solidarity with activists involved in an uprising against President Bashar al-Assad's rule.
A US spokesman said Mr Ford had left Damascus at the weekend after "credible threats against his personal safety".
In response, Syria said it had recalled its ambassador to Washington for consultations.
Ambassador Imad Moustapha left Washington on Monday, an embassy spokeswoman told the Associated Press.
Denouncing crackdownIn Syria last month, Mr Ford and colleagues were pelted with eggs and tomatoes when visiting an opposition figure.
He was then briefly trapped in his office by pro-Assad demonstrators.
An official at the US embassy in Damascus told the Associated Press Mr Ford had not been formally recalled.
Mark Toner, a spokesman for the US state department, said Mr Ford's return to Syria would depend on an "assessment of Syrian regime-led incitement and the security situation on the ground".
"We hope that the Syrian regime will end its incitement campaign against Ambassador Ford," he said.
